react-native-jieba

Native Chinese text segmentation for React Native, powered by cppjieba.

• Runs on the New Architecture as a C++ Turbo Module — no bridge overhead, no JS port of jieba.
• Ships the cppjieba dictionaries (jieba.dict.utf8, hmm_model.utf8, idf.utf8, stop_words.utf8, user.dict.utf8) inside the package, bundled as iOS pod resources and Android assets.
• Supports the standard jieba modes: precise (cut), full (cutAll), search engine (cutForSearch), HMM (cutHMM), small-word (cutSmall), POS tagging (tag), and TF-IDF keyword extraction (extract).
• Works on web (react-native-web) via jieba-wasm, with the same API.

Requirements

• React Native 0.85+ with the New Architecture enabled.
• iOS 15.1+, Android minSdkVersion 24+.
• C++20 toolchain (default on recent Xcode and Android NDK 26+).

Installation

npm install react-native-jieba
# or
yarn add react-native-jieba

iOS:

cd ios && pod install

Android: no extra steps — autolinking picks up the AAR.

Web (react-native-web): install the optional jieba-wasm peer dependency, which provides the WebAssembly backend.

npm install jieba-wasm

Any bundler that handles .wasm assets (Vite, Webpack 5, Metro-web, etc.) will bundle the binary automatically.

If you use Vite, exclude jieba-wasm from dependency pre-bundling so its .wasm is served from the package directory (otherwise the binary isn't copied into .vite/deps and the fetch 404s):

// vite.config.js
export default {
  optimizeDeps: { exclude: ['jieba-wasm'] },
};

Usage

On native (iOS/Android) there is no setup — just call cut, tag, etc. The dictionary is located/extracted automatically: on iOS the path is resolved from the app bundle, and on Android the bundled assets are extracted to filesDir/jieba-dict/ on the first call.

import { cut } from 'react-native-jieba';

cut('我来到北京清华大学');
// ['我', '来到', '北京', '清华大学']

prepareJieba() is an optional async warm-up on native: on Android's first run the asset extraction happens off the call site (asynchronously), avoiding a one-time blocking pause on the first cut/tag. On web it is required — it loads the jieba-wasm binary, which cannot happen synchronously. Use isJiebaReady() to check synchronously whether segmentation can run.

import {
  prepareJieba,
  isJiebaReady,
  cut,
  cutAll,
  cutForSearch,
  tag,
  extract,
} from 'react-native-jieba';

// Native: optional warm-up. Web: required (loads wasm).
await prepareJieba();

isJiebaReady(); // true

cut('我来到北京清华大学');
// ['我', '来到', '北京', '清华大学']

cutAll('我来到北京清华大学');
// ['我', '来到', '北京', '清华', '清华大学', '华大', '大学']

cutForSearch('小明硕士毕业于中国科学院计算所');
// ['小明', '硕士', '毕业', '于', '中国', '科学', '学院', '科学院', '中国科学院', '计算', '计算所']

tag('我爱北京天安门');
// [{ word: '我', tag: 'r' }, { word: '爱', tag: 'v' }, ...]

extract('我是拖拉机学院手扶拖拉机专业的。', 5);
// [{ word: '手扶拖拉机', weight: 10.01 }, ...]

API

On native, all segmentation calls are synchronous JSI calls — no Promises. On web they are synchronous too, but prepareJieba() must finish first (it loads the wasm module).

Function	Signature	Notes
prepareJieba(options?)	(options?: { wasmUrl?: string | URL | Request }) => Promise<void>	Web: must be awaited once before any other call. Native: optional warm-up — calling segmentation directly works too. Idempotent. wasmUrl is web-only and rarely needed (override where the .wasm is served).
isJiebaReady()	() => boolean	Synchronous check for whether segmentation can run now. Native-backed (reflects the real engine state, not whether prepareJieba was called): true on iOS from launch, true on Android once the dict is resolved (eagerly via prepareJieba or lazily on the first call).
cut(sentence, hmm?)	(string, boolean) => string[]	Precise mode. hmm defaults to true.
cutAll(sentence)	(string) => string[]	Full mode (every possible word).
cutForSearch(sentence, hmm?)	(string, boolean) => string[]	Search-engine mode.
cutHMM(sentence)	(string) => string[]	HMM-only segmentation.
cutSmall(sentence, maxWordLen)	(string, number) => string[]	Limits the maximum word length.
tag(sentence)	(string) => Array<{ word, tag }>	Part-of-speech tagging.
extract(sentence, topK?)	(string, number) => Array<{ word, weight }>	TF-IDF keyword extraction. topK defaults to 5.
insertUserWord(word, tag?)	(string, string) => boolean	Adds a user dictionary word at runtime.
find(word)	(string) => boolean	Tests whether a word is in the dictionary.

Web support

On web the implementation is backed by jieba-wasm (jieba-rs compiled to WebAssembly) instead of cppjieba. The core API is identical, with a few caveats because jieba-wasm exposes a smaller surface:

Function	Web behavior
cut, cutAll, cutForSearch, tag	Fully supported.
insertUserWord	Supported (maps to jieba-wasm add_word); the tag argument is honored, frequency is auto-assigned.
cutHMM	Falls back to cut(sentence, true) (jieba-wasm has no HMM-only mode).
cutSmall	Falls back to cut; the maxWordLen argument is accepted for parity but ignored.
find	Approximated: returns true when the word survives precise (non-HMM) segmentation as a single token.
extract	Not supported — throws. jieba-wasm does not ship the IDF dictionary needed for TF-IDF extraction.

Example (Vite + react-native-web)

// vite.config.js
import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';

export default defineConfig({
  plugins: [react()],
  resolve: {
    alias: { 'react-native': 'react-native-web' },
  },
  // jieba-wasm resolves its `.wasm` via `import.meta.url`; pre-bundling into
  // `.vite/deps` would leave the binary behind, so exclude it.
  optimizeDeps: { exclude: ['jieba-wasm'] },
});

// App.tsx
import { useEffect, useState } from 'react';
import { Platform, Text, View } from 'react-native';
import { prepareJieba, cut, cutForSearch, tag, extract } from 'react-native-jieba';

export default function App() {
  const [words, setWords] = useState<string[] | null>(null);

  useEffect(() => {
    // On web this loads + instantiates the wasm module (async) and is required.
    // On native you can skip this and call cut() directly.
    prepareJieba()
      .then(() => {
        setWords(cut('我来到北京清华大学'));
        // → ['我', '来到', '北京', '清华大学']

        cutForSearch('小明硕士毕业于中国科学院计算所');
        // → ['小明', '硕士', '毕业', '于', '中国', '科学', '学院', ...]

        tag('我爱北京天安门');
        // → [{ word: '我', tag: 'r' }, { word: '爱', tag: 'v' }, ...]

        // extract() throws on web — guard it for cross-platform code.
        const keywords = Platform.OS === 'web' ? [] : extract('…', 5);
      })
      .catch((e) => console.error(e));
  }, []);

  if (!words) return <Text>Loading…</Text>;
  return (
    <View>
      {words.map((w, i) => (
        <Text key={i}>{w}</Text>
      ))}
    </View>
  );
}

To self-host the binary (CDN or custom path), pass wasmUrl:

await prepareJieba({ wasmUrl: 'https://cdn.example.com/jieba_rs_wasm_bg.wasm' });

How it works

• The Turbo Module lives in cpp/JiebaImpl.{h,cpp} and wraps cppjieba::Jieba as a JSI Cxx module.
• iOS resolves the dictionary directory from NSBundle in ios/OnLoad.mm before the module is registered, so segmentation works immediately and prepareJieba() is a no-op on iOS.
• Android ships the dictionary as AAR assets and extracts them to filesDir/jieba-dict/. This happens automatically: if prepareJieba() is never called, the C++ module extracts them synchronously on the first segmentation call via an fbjni call into JiebaDict.extractDictDirFromNative (a one-time cost). prepareJieba() does the same extraction asynchronously up front (through JiebaAndroidHelperModule → the codegen-exposed setDictPath JSI method) so that first call doesn't block.
• isJiebaReady() is backed by the codegen-exposed isReady() JSI method, which reads the native engine state directly — so it stays correct even when the dictionary is resolved lazily on the first call.
• cppjieba and its limonp dependency are vendored as git submodules under cpp/cppjieba/. The published npm tarball contains only the headers and dictionaries that are actually needed at build time.
• On web, react-native-web's bundler resolution picks up src/NativeJieba.web.ts and src/init.web.ts. prepareJieba() lazily imports jieba-wasm, awaits its async wasm initializer, and routes the JS API to the wasm exports.

Contributing

This repository uses git submodules. Clone with:

git clone --recursive https://github.com/leonsilicon/react-native-jieba.git
# or after a plain clone:
git submodule update --init --recursive

• Development workflow
• Sending a pull request
• Code of conduct

License

react-native-jieba is MIT-licensed. The bundled cppjieba and limonp projects are MIT-licensed; their respective LICENSE files are included inside cpp/cppjieba/ and cpp/cppjieba/deps/limonp/.